The invention relates to a method and a device for adjusting a seat.
DE 10 2004 062 084 B3 relates to a device for automatically adapting a seat to the driver of a motor vehicle, the seat adjustment selected by the driver being detected and compared with stored target values. The actual detected values are adapted to the target values with the aid of components of the seat itself, by configuring these components to rest against the driver or by generating values of at least one person-specific parameter resulting from the action of the driver on the seat components. In doing so, a drive operated by an electric motor causes a seat component to rest against the driver. The electric motors are designed such that they turn off or switch over in the case of a predetermined mechanical resistance.
A disadvantage of the device disclosed in the document cited above is that the suggested measurement involves a high dead time until inferences can be drawn on the body mass of the driver. The mechanical adjustment involves a constant waiting time while the electric motor uses a lot of electricity. Moreover, it is not possible with this approach to determine the load applied by the user to the largely flat surfaces of the seat. Furthermore, the approach of electricity measurement is not precise.
It is the object of the invention to avoid the disadvantages cited above and to particularly specify a possibility of adapting a seat automatically and efficiently to an individual user from ergonomic aspects, the adaptation being carried out rapidly and with the aid of a measuring procedure that does not attract the user's attention.
With the aim of achieving this object, a method is provided for adjusting a seat as a function of a pressure exerted by a user on the seat, the pressure being detected with the aid of at least one pneumatic sensor and/or at least one hydraulic sensor.
In particular, the seat may be adjusted as a function of a pressure ratio determined with the aid of at least two pneumatic or hydraulic sensors.
A pressure distribution on the backrest and/or seating area(s) can thus be determined with the aid of the at least one sensor rapidly and without attracting the user's attention. This pressure distribution can be used for adjusting the seat, such as by drawing a comparison with target values.
In a development of the invention, the seat may include several pneumatic sensors and/or hydraulic sensors, at least one pneumatic sensor being connected to at least one pneumatic lifting element and/or at least one hydraulic sensor being connected to at least one hydraulic lifting element. The at least one sensor may have a fluidic connection to the at least one pneumatic and/or hydraulic lifting element via a line.
The lifting element thus has a dual function in that, on the one hand, it acts corresponding to its main function as an actuator, with the aid of which an actuation is applied to the contact surface of the user with the seat in order to achieve a massaging effect, for example. On the other hand, the lifting element functions as a pressure transducer in that the contact force applied by the user to the seat brings about a change of pressure in the interior of the lifting element. A pressure sensor detects this internal pressure of the lifting element.
The method of the invention as described above can thus be implemented with minimum additional effort since additional pressure transducers, for example, in the form of a sensor mat sewed in the backrest and/or the seat cushion, are not necessary.
In another development of the invention, a predetermined fill level may be assigned to the at least one hydraulic lifting element and/or the at least one pneumatic lifting element before the user exerts pressure on the seat; that is to say, before the user sits down in the seat.
In another development of the invention, a current pressure profile may be determined as a function of the pressure exerted by the user on the seat.
In particular, the pressure profile can correspond to a pressure distribution along the seat region.
In another development of the invention, the current pressure profile may be compared with a predetermined ergonomic pressure profile, and the seat and/or components of the seat is/are adjusted in the direction of the ergonomic pressure profile.
In particular, the seat can be adjusted automatically such that the ergonomic seat profile is achieved. It is also possible to use a closed-loop control system for this purpose, which carries out an iterative adjustment of the seat in the direction of the ergonomic seat profile with the help of the continuously updated data of the sensors.
In particular, a control unit can be provided, with the help of which the data of the sensors can be detected and the lifting elements can be controlled. At least one ergonomic pressure profile may be stored in the control unit.
Furthermore, in another development of the invention, the fill level of the at least one hydraulic lifting element and/or the at least one pneumatic lifting element may be reset upon completion of the seat adjustment. In doing so, the fill level can be reset to a previous value. Alternately, the at least one lifting element can also be emptied completely and/or partly.
In another development of the invention, the seat adjustment may be initiated when entering into a vehicle and/or when opening the vehicle and/or when approaching the motor vehicle.
For example, the seat adjustment can be initiated as early as when activating a remote control for opening the vehicle. It is also possible in combination with a keyless access system to automatically recognize the approximation of the user to his vehicle and accordingly initiate the seat adjustment.
Such an initiation of the seat adjustment advantageously includes the pre-allocation of predetermined pressures to the lifting elements.
In another development of the invention, the seat adjustment may be activated manually or automatically during travel.
In one embodiment of the invention, the seat may be an electrically and/or hydraulically and/or pneumatically adjustable seat.
In doing so, one or more of the following seat parts can be adjusted:
(1) Seat length;
(2) Seat tilt, seat height, backrest inclination;
(3) Upper backrest, seat depth, backrest width;
(4) Lumbar support, lumbar support depth, lumbar support height;
(5) Headrest.
An adjustment of the upper backrest is possible in the case of backrests having a horizontally running bending axis. The seat depth is adjusted by adjusting a thigh support.
In another embodiment of the invention, the headrest of the seat may be adjusted in height and particularly along a longitudinal axis in the driving direction.
The possibilities of adjusting the seat can be retrieved one after the other or in a defined sequence. It is possible, in particular, to combine a group of adjustment possibilities into a common (partial) adjustment. For example, the seat tilt, seat height and backrest inclination (or upper backrest, seat depth, backrest width) can be adjusted together and the required duration or adaption process for adjusting the seat can be reduced on the whole.
For example, the automatic seat adjustment may be carried out as follows:
(1) Seat-height adjustment
(2) Seat-tilt adjustment
(3) Backrest-inclination adjustment
(4) Upper-backrest adjustment
This automatic seat adjustment may be preceded by a pre-adjustment of the longitudinal position of the seat by the user or the retrieval of that adjustment in the longitudinal position of the seat that has been stored for an individual user. However, it is naturally also possible for the seat-length adjustment within the aforementioned sequence to be carried out within the scope of the automatic seat adjustment of embodiments of the invention.
A readjustment or correction of the seat position may be carried out using the following parameters:
(5) Seat-tilt adjustment
(6) Backrest-inclination adjustment
If the ergonomic seat profile is not yet achieved upon completion of this sequence, the sequence may be restarted from the first step.
In one embodiment, the pressure may be determined with the aid of at least one additional pressure sensor that is independent of a lifting element. Furthermore, additional sensors of any kind can be provided in the seat or in the vehicle, which additional sensors are consulted for evaluating the seat position and/or the driving condition and thus for adjusting the seat.
In another embodiment of the invention, two sensors may be provided in different, spatially separate regions of the backrest. The sensors thus provide a pair of actual pressure values which is transmitted to the control unit. A quotient is calculated from these two values in the control unit and compared with a value stored in the control unit. The stored value represents that ratio of pressure values that results in the case of a seat that has been adjusted correctly from ergonomic aspects. In the next step, drives, such as electric drives, may adjust the seat according to a predetermined algorithm, for the purpose of an approximation of the quotient of the two measured pressure values (actual quotient) to the stored ideal value (target quotient). The adjustment of the seat is complete when the ideal value is reached. In order to reduce the duration of seat adjustment, it is sufficient in practice to reach the ideal value within a tolerance field.
The two regions of the backrest in which the pressure is detected may be an upper and a lower region of the backrest.
Similarly, a pressure-value quotient can also be determined in two different, spatially separate regions of the seat cushion. The sensors may be disposed in a front and a rear region of the seat cushion.
In another embodiment of the invention, the actual quotients both for the backrest and the seat cushion are determined. As a result, the “vertical” and “horizontal” pressure ratios are measured, and are subsequently made to match with the ideal ergonomic pressure ratios (target quotients) stored in the control unit by a control algorithm in the control unit by adjusting the seat and its components.
By forming a pressure ratio between two different regions in the backrest and/or in the seat cushion, the method of the invention described above can be used irrespective of absolute values for the pressure. The measuring procedure is thus uncoupled from the weight of the user. The user's weight, physique, size, etc. thus no longer play a direct role. It is thus not necessary to store different absolute pressure values in the control unit, which absolute pressure values correspond to an ideal ergonomic adjustment of the seat and its components.
The seat adjustment can be carried out more precisely with the aid of a larger number of pressure transducers and pressure sensors, but a sufficiently accurate seat adjustment is already possible in the case of two sensors in the backrest and in the seat cushion in each case.
The fill pressure in the lifting elements can be reset once the ergonomically correct seat adjustment is reached. This ends the phase in which the lifting elements are used as pressure transducers. The lifting elements can thus also be used again for their actual function.
Lifting elements are usually provided in the right and the left parts of the backrest and/or the seat cushion. In an embodiment of the invention, a common pressure sensor detects the pressure exerted by a user on corresponding lifting elements in the right and left parts of the seat. Experiments have shown that this results in a sufficiently precise seat adjustment which also takes into consideration situations where the user is seated or supported eccentrically in the seat.
The lifting elements are not used for adjusting the seat in the sense of changing the contour of the seat, but only as pressure transducers (for a limited period of time) with the help of whose feedback the seat is brought into its target position by independent actuators, such as electric actuators.
A device for adjusting a seat is also provided. The device includes a control unit that is configured such that the method described herein can be carried out on the control unit.
The aforementioned control unit can include at least a chip, particularly a microprocessor and/or a microcontroller. It can also be at least an Application Specific Integrated Circuit (ASIC) or the like.
The device for adjusting the seat can be an integral component of the seat or it can be formed separately in a centralized control unit.
In particular, an automatic seat comfort adjustment may be provided, which determines a pressure distribution of a user in the seat with the aid of pneumatic sensors particularly in the regions of the seating area and the backrest.
It is of advantage, for example, that massage seats or seats such as the ones described in DE 197 26 409 A1 often have lifting elements which are coupled to pressure sensors in order to rule out overloading or erroneous filling. These pressure sensors can be used as the sensors cited above.
Initially, the lifting elements may be pre-filled. This pre-filling can be carried out automatically as soon as a user approaches the vehicle, opens the vehicle, or opens a door to a seat of the vehicle.
The at least one sensor may register different pressures with the help of the pre-filled lifting elements depending on the size, weight, physique and position of the user sitting down in the seat.
The pressure distribution of the user in the seat can thus be determined. This pressure distribution is compared with a pressure distribution that would be considered as being advantageous from ergonomic aspects. Particularly the pressure distributions of the lifting elements can be set in relation to each other and compared with a previously determined and stored pressure distribution. This comparison delivers a difference that can be compensated for with the aid of the adjustment possibilities of the seat.
For such a seat adjustment, a defined period of time may be predetermined during which the seat is adapted to the previously stored pressure distribution. The adjustment or adaption may conclude with the lapse of this period. Alternately, the adaption to the seat position of the user can be carried out regularly or continuously. An adapted ergonomic adjustment can be rapidly found for the user particularly in the case of a change in the position of the seat.
Optionally, the seat adjustment can be started automatically or manually, for example, when driving for a long period of time.
Embodiments of the invention will be explained in more detail below.
In the use of seats having a plurality of adjustment possibilities, the user often finds it difficult to cope with the process of finding the correct or suitable seat adjustment. Furthermore, it may happen that a seat position that the user initially finds comfortable turns out to be uncomfortable or un-ergonomic after an extended period of sitting in the seat.
Embodiments of the invention enable the automatic adjustment of a seat position that is ergonomic for the user of the seat without requiring the user to know or learn the adjustment possibilities of the seat. Likewise, the user need not know the seat position that would be advantageous from ergonomic aspects.
It is thus possible to automatically adjust a seat position for the user which enables high level of seat comfort over a long period of time.
The adjustment of the seat as a function of the measurement of pressure exerted by a user on the seat with the load distribution derived therefrom is associated with a high level of comfort for the user.
The time taken for adjusting the seat is short particularly due to the high sensitivity of the filled lifting elements that enable rapid detection of the pressure distribution.
The approach presented here further enables a complete adjustment of the seat over a plurality of percentiles and anthropometries.
The functionality described can be used globally for different body shapes, and particularly also in cases where the driver's spinal column is deformed due to old age or illness.
The seat position can particularly be adjusted based on a tissue-pressure distribution that would be considered as optimum from medical and ergonomic points of view.
Apart from the automatic adjustment described above for achieving a permanently comfortable and advantageous seat position in terms of ergonomics and driving safety, the user also has the option of manually changing the seat adjustment.
Seats for carrying out the method of the invention are suitable for use in any kind of vehicle, particularly in a motor vehicle. The seat can be a driver seat, front passenger seat or any other passenger seat.
Other objects, advantages, and novel features of the present invention will become apparent from the following detailed description of one or more exemplary embodiments when considered in conjunction with the accompanying drawings.